Process for producing polyester textured yarn

ABSTRACT

A process for producing a polyester textured yarn which comprises drawing and simultaneously false-twisting an undrawn polyester yarn using a draw texturing apparatus equipped with a heat-treating heater and a false twister between feed rollers and draw rollers, wherein the undrawn polyester yarn has a birefringence ( Delta n) of 0.01 to 0.05, and the draw ratio (DR) is adjusted to a value expressed by the following equations according to the birefringence of the undrawn polyester yarn -1.8349 LOG Delta N-1.1376 &lt; OR = DR &lt; OR = -2.1789 log Delta n-1.3509 AND DR &lt; OR = 2.8.

United States Patent [191 Hori et al.

[ June 3, 1975 1 PROCESS FOR PRODUCING POLYESTER TEXTURED YARN [75]Inventors: Kikuo Hori; Hidehiko Okada;

Masakazu Fujita, all of Matsuyama, Japan [73] Assignee: Teijin Limited,Osaka, Japan [22] Filed: Aug. 13, 1973 [21] Appl. No.: 387,629

[30] Foreign Application Priority Data Aug. 17, 1972 Japan 47-81782 [52]US. Cl 57/157 TS [51] Int. Cl D02g 1/00 [58] Field of Search 57/34 HS,157 R, 157 S, 57/157 TS, 157 MS, 160

[56] References Cited UNITED STATES PATENTS 3,090,997 5/1963 Tin-Yam Au57/157 S UX 3,137,991 6/1964 Fairley 57/160 3.400,]94 9/1968 Boone eta1. 57/157 S X 3,481,136 12/1969 Timmons et a1 57/157 S X 3,691,750 9/ l972 Waters 3.780515 12/1973 Waters 57/157 R Primary ExaminerDonald E.Watkins Attorney, Agent, or Firm-Sherman & Shalloway [57] ABSTRACT Aprocess for producing a polyester textured yarn which comprises drawingand simultaneously falsetwisting an undrawn polyester yarn using a drawtexturing apparatus equipped with a heat-treating heater and a falsetwister between feed rollers and draw rol-' lers, wherein the'undrawnpolyester yarn has a birefringence (An) of 0.01 to 0.05, and the drawratio (DR) is adjusted to a value expressed by the following equationsaccording to the birefringence of the undrawn polyester yarn -l.8349 log'A nl.l376 DR and 2.l789 log A 17 Claims, 5 Drawing Figures PATEIHEBJUHB197s 3.886722 SHEET 2 DRAW RATIO BIREFRINGENCE (AD) Fig. 5 6.0" I

|s0 I250 TEMPERATURE OF HEAT-TREATING HEATER ('0) DEGREE OF DYEEXHAUSTION PROCESS FOR PRODUCING POLYESTER TEXTURED YARN This inventionrelates to a method of producing polyester textured yarns. Morespecifically; this invention relates to a method of producing texturedyarns which comprises drawing an undrawn yarn of a polyester using adraw texturing apparatus including a heattreating heater and a falsetwister between feed rollers and draw rollers, and simultaneouslyfalse-twisting it to form a textured yarn.

In recent years, a method of producing a textured yarn from an undrawnyarn in a single step has been in use, in which an undrawn yarn ofpolyester is drawn and simultaneously twisted. Although this method isvery efficient as compared with the conventional method in which drawingand twisting are performed separately, there is a defect that because ofthe occur rence of fluffs, loops, tight spots, dyeing unevenness, etc.,textured yarns of fully satisfactory quality cannot be obtained.

It is an object of this invention to provide a drawtexturing processcapable of providing textured yarns free from these defects.

We have found that the above object can be achieved by selecting anundrawn yarn of a specific birefringence and a specific draw ratio isselected according to the birefringence of the undrawn yarn.

According to this invention, there is provided a method of producingpolyester textured yarns which comprises drawing and simultaneouslyfalse twisting an undrawn yarn of a polyester using a draw texturingapparatus equipped with a heat-treating heater and a false twisterbetween feed rollers and draw rollers, wherein the undrawn yarn ofpolyester has a birefringence (An) of 0.01 to 0.05, and the draw ratio(DR), that is, the ratio of the peripheral speed of the draw rollers andthat of the feed rollers. is adjusted to a value which satisfy thefollowing equation according to the birefringence of the undrawn yarnl.8349 logAn 1.1376 DR 2.l789 logAn The polyester undrawn yarn," as usedin the present specification and appended claims, generically denotes asubstantially unoriented multifilament yarn composed of polyethyleneterephthalate or a copolymer at least 85 mol of which are ethyleneterephthalate units. The denier, and cross sectional configuration ofthe multifilament yarn and the addition of an additive thereto. etc. canbe selected as desired. For textured yarns having good feel, undrawnyarns having a denier size of 30 to 1,000 denier are especiallypreferred.

In the present invention, the polyester undrawn yarns having abirefringence (An) of 0.01 to 0.05, preferably 0.01 to 0.025, are used.The birefringence of the undrawn yarn varies according to such factorsas the composition, and inherent viscosity of the polyester, thespinning temperature, spinning speed, or the cooling conditions. Bycontrolling these conditions, undrawn yarns having a birefringence of0.01 to 0.05 can be easily produced. 7

For example, when polyethylene terephthalate having an inherentviscosity (as measured in ochlorophenol at 35C.) of 0.6 is spun at 300C.using a conventional spinning apparatus, and wound up at various rates,the birefringence of the resulting filament changes as shown below.

Windup rates If an undrawn yarn of polyester in this invention is lessthan 0.01, breakage of the yarn frequently occurs at the time of yarnstringing, and the efficiency of the yarn stringing and the productivitybecome poor. In addition, tight spots tend to occur and the undrawn yarndrastically changes with the passage of time, making it impossible toproduce a textured yarn of uniform quality. On the other hand, with anundrawn yarn having a birefringence exceeding 0.05, non-uniformity inthe spinning process is remarkable, and this non-uniformity cannot beobviated even by draw texturing techniques. thus making it impossible togive a textured yarn of uniform quality.

In the present invention, it is preferred that an undrawn polyester yarnwhich has been subjected to aging under the temperature (TC.)-time (2hours) conditions be submitted to a draw texturing process. In thiscase, a textured yarn having especially reduced occurrence of dyeingunevenness can be obtained.

Aging conditions:

where 20C. T 30C., (2.604 0.0486T) I 2ll.2T+ 6424 where 30C T 40C.,(2.604 0.04867") An alternative method of obtaining a textured yarnhaving especially reduced occurrence of dyeing uneveneness involves theuse of an undrawn polyester yarn whose moisture content is maintainedalways at not more than 1.0% preferably not more than 0.5%, during theperiod from the end of spinning until the draw texturing process.Adjustment of the moisture content of the undrawn yarn to such a lowvalue can be easily achieved by treating the undrawn yarn with an oilingagent having a low moisture content or having substantially no moisturecontent in the spinning step.

FIG. 1 is a side elevation in simplified form of a suitable apparatusfor performing the method of the invention;

FIG. 2 is a sectional view illustrating a preferred embodiment of thisinvention for performing the method of this invention using a modifiedhot-plate type heater;

FIG. 3 is a graphic representation showing the relation between drawratio, and birefringence;

FIG. 4 is a side elevation illustrating still another embodiment of anapparatus usable in this invention;

FIG. 5 is a graphic representation showing the relationship between yarnparameters of this invention.

FIG. 1 of the accompanying drawings is a side elevation in simplifiedform of one example of a suitable apparatus for performing the method ofthis invention. In FIG. 1, the'reference numeral 1 shows a package of anundrawn yarn; 2, a tensioner; 3, feed rollers; 4, a heattreating heater;5, a false-twisting spindle; 6, draw rollers; and 7, a winder. Theundrawn yarn is withdrawn from the package 1, and fed at a constantspeed by the feed rollers 3 via the tensioner 2. After making slidingcontact with the heat-treating heater 4, the undrawn yarn passes thefalse twisting spindle and reaches the draw rollers 6 which rotate at aconstant speed faster than the speed of the feed rollers. During thistime. the undrawn yarn is drawn at a draw ratio (DR) corresponding tothe ratio of peripheral speed between the draw rollers 6 and the feedrollers 3, and the false twists given to the yarn by the false-twistingspindle 5 are heat-set by the heat-treating heater 4. The false twistsare detwisted after passage of the yarn through the false twistingspindle 5. The position of the undrawn yarn on the heat-treating heateris fixed by a guide located upwardly of the heater 4 and a guide locateddownwardly of the heater 4, and the feeding position of the yarn to thefalse twisting spindle 5 is fixed by a guide located upwardly of thespindle 5. The drawn yarn which has left the draw rollers 6 developscrimps -while being wound up by the winder 7 after passing the guide.The draw texturing speed is usually 75 to 600 m/min.

The heat-treating heater is not limited to a hot plate type as shown inFIG. 1, but other known types such as a slit heater or tube heater canbe used. Preferably, the temperature of the heat-treating heater is 160to 210C. When temperatures within this range are employed, texturedyarns having especially good leveldyeability and crimp properties withextremely reduced occurrence of fluffs or tight'spots can be obtained.

According to another preferred embodiment of this invention, thesurfaces of the feed rollers 3 are maintained at a temperature of 60 to120C., and the undrawn yarn is brought into contact with the surfacesfor at least 0.05second. By this procedure, the point of drawing isfixed between the feed rollers 3 and the heat-treating heater 4,'and theoccurrence of drawing uneveaeness, dyeing uneveneness, yarn breakage,and fluffs, etc., is remarkably reduced.

' FIG. 2 of the accompanying drawings is a sectional view forillustrating a preferred embodiment of this invention for performing themethod of this invention using a modified hot plate-type heater 4'instead of the hot plate shown in FIG. 1. In FIG. 2, the referencenumeral 1 shows an. undrawn yarn, and the reference numeral 9 shows onemember of a pair of walls arranged in parallel with each other with aslit therebetween in the longitudinal direction of the heater 4'. Inthis embodiment, the undrawn yarn 1 does not come into contact with theheated surface of the heater from the inlet of the heater to a positionapart from it by distance I mm., but is preheated at a temperature of 60to 150C. within the slit space confined by the wall 9. The undrawn yarnis subsequently brought into contact with the heated surface of theheater. The distance I should satisfy the following equations.

and

0.03 .r 0.2 1 51 0.3x 2y 100 wherein x is the denier size of the undrawnyarn. and y is the feed rate (m/min) of the undrawn yarn. If the undrawnyarn is heat-treated under theseconditions, the point of drawing isfixed between the point ofinitial contact of the undrawn yarn with theheated surface of the heater and a point 30 mm away from it. andtherefore, a textured yarn having especially superior crimp propertiesand reduced occurrenceof tight spots, dyeing uneveneness and fluffs canbe obtained.

The rotating speed of the false-twisting spindle 5 is preferablycontrolled such that the twist multiplier a expressed by the followingequation is within the range of 0.85 and 1.15.

wherein .r is the number of false twists (T/M), and De is the denier ofthe drawn yarn.

It is essential in the present invention that the ratio of the periperalspeed of the draw rollers 6 to that of the feed rollers S, that is, thedraw ratio (DR), be adjusted to a value expressed by the followingequations according to the birefringence (A n) of the undrawn yarn, forexample within the range of 2.2 to 2.8. l.8349 logAn 1.1376 5: DR-2.l789 logAn FIG. 3 of the accompanying drawings is a graphicrepresentation showing the relation between the draw ratio and thebirefringence. In performing the method of this invention, the drawratio and birefringence values within the hatched area in FIG. 3 shouldbe selected. If the draw ratio is lower than this range, the un drawnyarn melt-adheres onto the heat-treating heater, and yarn stringing isdifficult. Moreover, the level-dyeability becomes poor, and the tenacityis reduced. On the other hand, if the draw ratio is higher than therange specified above, fluffs and loops tend to occur, and the crimpcharacteristics of the yarn become poor. Furthermore, when the drawratio becomes too high, the tenacity of the yarn rather decreases.

As is clear from FIG. 3,the draw ratio employed in the method of thisinvention is considerably lower than those employed in usual drawingprocesses. It is surprising that in spite of the use of such low drawratios, the method of this invention makes it possible to give a textureyarn having no fluffs or loops and having superior level-dyeability,methanical properties and crimp characteristics.

Another embodiment is possible in this invention in which at least 2yarn guides are provided between the false twister and the draw rollersto bend the yarn at a certain angle, and the total sum of the bendedangles caused by these guides is adjusted to 30 to 270C,

preferably 30 to FIG. 4 is a side elevation illustrating this embodimentof this invention. The reference numeral shows a false twisting spindle,the reference numerals 8, 8 and 8" show yarn guides, and the referencenumeral 10 designates draw rollers. Of course, the draw rollers 10 maybe replaced by the draw rollers 6 shown in FIG. 1. In this embodimentalso, it goes without saying that package tensioner 2, feed rollers 3,heat-treating heater 4, winder 7, etc. must be arranged as shown in FIG.1.

According to this embodiment. as shown in FIG. 4, at least two yarnguides 8, 8', 8" are provided between the false twisting spindle 5 andthe draw rollers 10, and the total sum of the bended angles 01,. a a(Ea) is adjusted to 30 to 270, preferably 30 to 150. This total sum ofthe bended angles is very important for detwisting the false twistscompletely and-exhibitingthe'crimp characteristics fully. If the totalsum is less than 30, the false twistsare not sufficiently detwisted, andtight spots occur partly in the lengthwise direction of the yarn. On theother hand. if the total sum exceeds 270, resistance caused by theguides becomes excessive, and fluffs occur. Furthermore, the crimpcharacteristics become poor. However, if the total sum is within therange specified in this invention, the false twists are completelydetwistdd, and the crimp characteristics are improved and the occurrenceof ballooning is very much reduced. Furthermore, the number of the yarnguides is also of importance. If it is only one, uniform detwisting cannot be performed even if the bended angle of the yarn is adjusted tomore than 30. In order to give a bended angle of more than 30 using oneguide, the guide must be provided at a position greatly deviated fromthe center of the false twisting spindle. However, if it is disposed insuch a way, the yarn comes into contact with the edge of the spindle andexcessive load is exerted on the yarn, which in turn becomes a cause offluffs and poor crimps. Accordingly, it is necessary to provide at leasttwo yarn guides.

False twisting can also be performed using known false-twisting means,for example, by applying friction or by a swirling flow of fluid. In theexample shown in FIG. 4, the bended direction of the yarn is at rightangles to the axial direction of the draw rollers, but may be in theparallel direction to the axial direction of the draw rollers. Further,bendings in both directions may be combined as desired.

The shape and dimension of the yarn guide are not particularlyrestricted, but preferably, the guide nearest the false twister is anannular guide, and the other guides are rod-like guides. Further, theguides may be either fixed guides or rotating guides. The surface of theguides may either be smooth or embossed. However, especially by usingfixed guides with smooth surfaces of not more than 18, the effect ofpreventing tight spot is remarkable. In addition, by the contactingeffect of the guides, the crimp characteristics of the yarn are improvedto a great degree. The material of the guides may be thoseconventionally used, for example, saphire, titanium porcelain, aluminaporcelain, or chrome-plated metals.

According to another embodiment of this invention, the process iscontrolled so that the yarn is made to run in air at room temperaturefor 0.13 to 0.3 second between the heat-treating heater and the falsetwister. This makes it possible to obtain a textured yarn having highdegrees of crimp and crimp fastness and reduced tight spot.

According to still another embodiment of this invention, a secondheat-treating heater (not shown) is provided following the draw rollers6 or 10, and enables the draw textured yarn from the draw rolls to beadditionally heat-treated at a temperature of 160 to 250C. whileallowing a shrinkage of not more than 50% or while maintaining it atconstant length. Thus, the control of the degree of crimping and theimprovement of dimensional stability against heat are possible.

The textured yarns produced by the method of this invention are almostfree from fluffs, loops and tight spots, and have superior crimpcharacteristics and mechanical properties and also goodlevel-dyeability. These textured yarns have the advantage that theamount of dye exhaustion does not change even when the temperature ofthe heat-treating heater fluctuates between 160 and 210C.

FIG. 5 is a graphic representation showing the relation between thedegree of dye exhaustion and the tem perature of the heat-treatingheater with respect to the texture yarn obtained in the presentinvention and an ordinary texture yarn. Curve A in this FIG. refers tothe textured yarn obtained in this invention, and curve B, to theconventional texture yarn. As is clear from this Figure, with thetexture yarn (A) in accordance with this invention, there is scarcelyany change in the degree of dye exhaustion when the temperature of theheat-treating heater is within the range of 160 to 210C. However, withthe conventional texture yarn (B), the degree of dye exhaustion changeswith the temperatures of the heat-treating heater. Thus, even a slightflurctuation in the temperature of the heater results in dyeinguneveness.

The degree of dye exhaustion denotes the grade of the depth of colorobserved by the naked eye with a textured yarn which has been dyed bydipping it for minutes in a boiling dye bath containing 2% of EastmanPolyester Blue GLF (CI DISPERSE BLUE 27). Larger numerical values showdeeper color.

In the performance of the present invention, various auxiliary means canbe employed at the time of initiating the operation or at the time ofcontinuous operation.

Examples of the auxiliary means at the time of initiating the operationare:

1. A method wherein without bringing the yarn into contact with theheat-treating heater, the operation is started using a twist multiplier50 to 85% of that in normal operation, and then the yarn is brought intocontact with the heat-treating heater.

2. A method wherein the operation is started at a draw texturing speedexpressed by the equation.

wherein V is the draw texturing speed, and yarn stringing is performed,and then the draw texturing speed is raised to a predetermined value.

3. A method wherein at the time of initiating the operation, yarnstringing is performed while the undrawn yarn is maintained so as not tocome close to the surface of the heat-treating heater, and then the drawtexturing of the yarn is started while passing the yarn throughia zonenear the surface of the heat-treating heater which zone is held at 50 toC, and then the yarn is {brought into contact with the heat-treatingheater.

If such auxiliary means are applied, the breakage of yarn at the time ofinitiating the draw texturing process and at the time of contacting theyarn with the heattreating heater can be substantially prevented, andtherefore, the efficiency of the yarn stringing operation and theworking efficiency of the draw texturing apparatus are drasticallyincreased.

Examples of the auxiliary means at the time of con tinuous operationare:

1. A method wherein the end of the undrawn yarn on the package and theforward end of the undrawn yarn on the package are cold drawn and tiedbefore the package of the undrawn yarn being processed becomes arearranged in a plurality of rows, and the transfer of the yarn isperformed between two packages facing each other on the vehicles.

If such auxiliary means are applied, it is possible to perform the drawtexturing process of this invention continuously.

The following Examples illustrate the present invention.

The measurement values in the Examples were obtained by the followingmethods.

1. Loops and Fluffs The number of fluffs and loops appearing on both endsurfaces of 2.5 Kg of a square end cheese (wind-up width 150 m).

2. Tight spot The number of untwisted portions (portions remainingalternately twisted in the yarn without detwisting as a result ofheat-fusing of filaments to each other) per 10 m of the processed yarn.

3. Degree of total crimp (TC) An initial load (2 mg/d) and a heavy load(0.2 g/d) were exerted at the same time on a processed yarn of aconstant length, and after a lapse of 1 minute, the length of the sampleyarn was measured and designated I Then, only the heavy load wasremoved, and the yarn was boiled in boiling water for minutes andallowed to dry spontaneously for 24 hours in a free condition. Then, theinitial load and the heavy load were exerted on the yarn at the sametime, and after a lapse of 1 minute, the length of the sample yarn wasmeasured, and made I Then, after removing only the heavy load, and aftera lapse of 1 minute, the length of the sample was measured and made 1 TCis expressed by the following equation.

4. Dyeing uneveness 5. Crimp fastness A load was exerted on a polyestertextured yarn, and the yarn was continuously stretched, and theelongation of the yarn at disappearance of the 'crimps and itselongation at break were measured. The crimp fastness was calculated bythe following equation.

Elongation at the disappearance of crimps Elongation at break X 100 (inCrimp fastness 6. Moisture content About 20 g of the undrawn yarnlocated 5 mm outwardly of the surface of the undrawn yarn bobbin and atthe central part with respect to the axial direction of the bobbin (thatis, the undrawn yarn present in the innermost layer of the package whichis not al all exposed to the outer atmosphere) was quickly sampled. Theresulting sample was completely dried, and placed in a bottle of a knownweight (W g), and the bottle was sealed with a lid. The bottle was thenprecisely weighed, and the weight was W The lid was removed, and thebottle was placed in a hot air dried held at a temperature of i 2C.After drying for 3 hours, the bottle was sealed with the lid and againprecisely weighed. The weight was W g. The moisture content (70) wascalculated as follows:

7. Different in dye exhaustion A standard sample was a texture yarnwhich was obtained by subjecting an as-spun undrawn yarn to drawtexturing within 8 hours. The standard sample and a sample to bemeasured were knitted side by side, and the knitted fabric obtained wasdyed in the same was as the dye exhaustion degree test mentioned above.The difference in dye exhaustion between the measuring sample and thestandard sample was evaluated on the resulting dyeings by the naked eyeon the scale shown below. The dye exhaustion difference shows an averagevalue of the dye exhaustion difference for 10 samples of the same level.

0: Not discriminatable +0.5: Slight difference +1.0: Difference fullyobserved +1.5: When the yarn having a dye exhaustion difference of 1.0was assumed to be a standard sample, there is a slight difference +2.0:A slight difference observed in the same way as above using a yarnhaving a dye exhaustion difference of 1.5

The plus symbol means that the sample was dyed deeper than the standardsample, and the minus symbol shows that it was dyed in lighter colorthan the standard sample.

EXAMPLE 1 Temperature of the heat-treating heater C Rotating speed ofspindle 30.1 X 10 rpm Twist multiplier 1.0 Draw ratio (DR) 3.14 to 1.30

Draw texturing speed 75.8 to 1 15.5 m/min.

The results are shown in Table 1 below.

Table 1 Run Undrawn Draw Yarn Loops and Tight TC Dyeing Overall DRtexturing stringing fluffs spots unevenness evaluation No. An speed per25 kg per 10 in W!) (m/min) M 00060 3.14 75.8 Frequent 23 3 5 32.6 .5Poor yarn break 1-2 0.0106 2.78 80.0 Good 2 0 1 34.3 4.5 Good l-3 0.01842.30 88.5 0 0 33.7 4.5 Excellent 1-4 0.0278 2.00 94.9 0 0 35.1 4.5 l-0.0387 1.70 102.9 0 0 32.5 4.5 l-o 0.0485 1.50 109.6 0 0 34.1 4.5 1-70.0552 1.35 115.5 0- 3 0 32.3 3.0 Fair EXAMPLE 2 EXAMPLE 4 An undrawnpolyethylene terephthalate yarn (30 2 denier/48 fil) having abirefringence of 0.0226 was subjected to draw texturing using anapparatus shown in FIG. 1, under the following conditions.

Temperature of the heat- An undrawn yarn (240 denier/24 filaments) ofpolyethylene terephthalate having an intrinsic viscosity of 0.0152 and abirefringence of 0.62 (containing 5 mol "/0 of isophthalate) wassubjected to draw texturing under the following conditions.

treating heater 180C. Rotating speed of the spindle 30.1 X 10 r/mTemperature f th hem. multiplier treating heater 175C. DR L8 to 4Rotating speed of the spindle 40.2 X 10" rpm Draw texturmg speed 1 14 to9) m/nun. Twist multiplier 9 DR 2.4 The results are shown in Table 2below.

Table 2 Run DR Yarn Loops and Tight 'lenacity Elongation TC DyeingOverall stringlul'fs spots unevenness evaluation No. ing per 10 m (g/d)(71) d Frequent 2 1 1.8 yarn 4 8 3.17 29.2 34.7 .5 Poor break 1 2-2 1.9Good 1 l 3.68 26.8 33.0 4.0 Good 2-3 2.0 0 0 3.72 25.3 32.8 4.5Excellent 2-5 2.2 l 0 3.65 20.1 31.9 4.0 Good 2-(\ 2.3 l5 0 3.24 18.530.4 3.5 Poor EXAMPLE 3 A polyethylene terephthalate undrawn yarn (366denier/ filaments) having a birefringence of 0.01 78 was subjected todraw texturing under the conditions shown in Table 3, using two types ofapparatus. The physical properties of the resulting texture yarns werecompared. The results are shown in Table 1.

Table 3 Run No. 3.1 3.2

Apparatus used Figure 1 Draw pin provided between feed rollers and a hotplate Processing conditions Temperature of the drawn pin 90C.Temperature of the hot plate of the heat-treating heater (C.) 200 210Rotating speed (rpm) of the spindle 41.5 X 10" 41.5 X 10" Twistmultiplier 0.98 0.98 DR 238 2.6 Draw tcxturing speed (m/min.) 161.6 1545Physical properties of the yarn Loops and fluffs per 2.5 kg 0 to 3 5 to15 TC (71) 34 30 Torque (T/25 cm) 20 42 Knittability Good With someproblem Lil I (to The resulting texture yarn was free from fluffs.loops, and tight spots, andex-hibited good crimpability with a TC of32.5 When this yarn was dyed in blue color, the color was brilliant, andthe yarn had good feel.

EXAMPLE 5 Three polyester undrawn yarns (A, B and C) shown in Table 4were each subjected to draw texturing under the conditions shown inTable 4 and varying the bended angles of the yarn using an apparatus asshown in FIG. 4 which included 1 to 3 guides between the false twistingspindle and draw rollers. The angle of pulling out the yarn from thespindle was adjusted to 20 in all cases. The results are shown in Table5. In Table 5, Runs Nos. 7, 8. 9, 12, 13 and 14 are examples of thepresent invention and the others are for comparative purposes.

" l l l 2 Table 5 Run Num- Undruwn yarn A B C her No. of Bending angleguides *4 *4 *4 Tight Loops and Tight Loops and Tight Loops and a, a:01;, 2a spots fluffs spots fluffs spots fluffs *1 5-3 1 24 24 1 l 5 9 025 0 5-4 35 35 4 3 l2 3 5-5 45 45 5 40 10 31% 6 41 5-6 8.5 9.0 17.5 24 56 0 l4 0 5-7 3 27 2 0 2 0 2 0 *2 5-8 2 25 47 72 1 1 0 I 0 1 5-9 52 78.5I30.5 0 I 0 l (J 0 5-10 145 145 290 2 25 0 I8 I 10 5-11 5.5 '4 15 24.5 30 l3 0 I8 0 5-12 5 5.5 25.7 36.2 0 0 0 0 0 (l Note: '1: Using only guide8 shown in FIG. 4. *2: Using guides 8 and ii shown in FIG. 4. 3: Usingguides 8. 8' und 8" shown in FIG. 4. '4: The bended angle shown in FIG.4.

EXAMPLE 6 25 EXAMPLE 7 An undrawn yarn (345 denier/30 fil,brirefringence 0.013) of polyethylene terephthalate having an intrinsicviscosity of 0.632 as measured in o-chlorophenol at C. was subjected todraw texturing using the apparatus of FIG. 1 under the conditions shownin Table 6.

Example 6 was repeated except that the surface temperature of the feedrollers was adjusted to 90C. and the time of contact between the undrawnyarn and the feed rollers was varied. The results are shown in TableTable 7 Run Contact time Tenacity Elon ution- TC Fluffs Tight spotsDyeing No. (seconds) (g/d) r) (7:) unevenness The yarn obtained washeat-treated at 200C. while al- EXAMPLE 8 lowing shrinkage of 14.8 andthen wound up. The results are shown in-Tab1e 6.

Temperature of the surface Polyethylene terephthalate chips having anintrinsic viscosity of 0.645 were spun at 291C. and taken up at 5 a rateof 2,000 m/min. to form an undrawn yarn (355 denier/30 fill havingbirefringence of 0.0145. In this Ofthe feed rollers to spinning process.an oil of the following formulation Time of contact of the undrawn n kyarn with the feed rollers 0.06 second was pp to the y y an mg er to anplc TemPemure a up of 1 The undrawn yarn was wound up, and a1- 61 9 8 50lowed to stand for 3 months in an atmosphere held at Draw ratio 2.45240C., and then subjected to draw texturing under the Draw texturingspeed 185 m/min. f ll i diti Table 6 Run Temperature of TenacityElongation T. C. Fluffs Tight spbts Dyeing No feed rollers per 10 munevenness (C) (g/d) ('70) Formulation of Oil A Mineral oil Ethyleneoxide-added olcyl alcohol Octyl phosphonic acid amine Oleic acidtriethanolamine Draw texturing conditions Draw ratio Temperature of theheattreating heater Number of twists Processing speed 80 "/1 by weight10 71 by weight 40 7: by weight 6 '7: by weight 2600 T/M 200 m/min.

The results are shown in Table 8.

EXAMPLE 10 This undrawn yarn as wound on a package was placed in anaging chamber, and aged under the conditions shown in Table 10.

the false twisting spindle and the total sum 1, a of the yarn bendedangles were changed. The results are shown in Table 9.

Table 8 Run State of oil Moisture content Moisture content Dyeexhaustion Dyeing immediately (71-) after difference unevenness No.after spinning allowing to stand for 3 (7r) months at 40C.

8-1 10 7: aqueous 3.5 2.5 +4 2.0

emulsion 8-2 6 7: aqueous 1.4 1.1 2 2.5

emulsion 8-3 aqueous 0.8 0.7 +0.3 4.5

emulsion 8-4 Straight oil 0 0.2 0.3 4.5 8-5 2-stage oiling 0.5 0.5 +0.54.5

.* Z-stage oiling: first stage 1 aqueous solution of sodium dioctylsulfosuccinate .second stage =straight oil EXAMPLE 9 Table 10Polyethylene terephthalate having an intrinsic viscos- I ity of 0.645 asmeasured in o-chlorophenol at C. li fl jg gf g Agmgtme was spun at 292C.and taken up at a speed of 1,7800 35 in the aging (hours) m/min. to forman undrawn yarn having a 1,800 of Chamber 0.0135 and a denier of 360denier per 30 filaments. 4 10 24 The undrawn yarn was subjected to drawtexturing :8; 5g 2; using an apparatus of the type shown in FIG. 1except 104 5 that the false-twisting spindle and the draw rollers werelg-g g2 22 replaced by those shown in FIG. 4, and a second heat- 26 3treating heater was equipped, under the following con- 10-8 26 600ditions. At this time, the time during which the yarn ran between theoutlet of the first heat-treating heater and 45 After aging, the undrawnyarn package was transported to a drawing and false-twisting factoryremote from the spinning factory. The time which elapsed from the end ofaging to the initiation of drawing and false- ?g f twisting was about 20hours, and the temperature durfirst eat-treating 210C. ingtransportation was 24 to 29C.

eater Temperature of the The drawing and false-twisting was performedunder second heat-treating 205C. t heater the following conditions in achamber maintained at a Number of twists 2590 temperature of 27C i 2Cand a relative humidity of Draw texturing speed 200 m/min. i 5

Table 9 Run Time of Yarn Tenacity Elongation Degree of Crimp Tight spotsFluffs yarn bended crimps fastness per 20 in No travel angle (seconds)(a,+a (g/d) 4. The process of claim 1 wherein the undrawn yarn Draw p isone whose moisture content is maintained always at t e 195cc not more1.0 7: by weight from the end of spinning (hm p at d to the 1n1t1at1onof draw texturmg.

1 meters/min 5. The process of claim I wherein the undrawn yarnlltlumhcr of fill thwists 2590 TM is brought into contact with thesurfaces of feed rollers t re 1) t 'ggg fi l c 205C heated at 60 120C.for at least 0.05 second. I il 1h d 6. The process of claim 1 whereinthe heat-treating hez i lgr on e beam 14,87. 10 heater is heated to from160 to 210C.

. 7. The process of claim 1 wherein the process is car- T p p of theresultmg Polyester textured ried out while maintaining a twistmultiplier expressed yarns are shown in Table 1 1. by the f ll iequation Table 11 Run Tenacity Elongation Dyeing Dyeing Fluffs TightProcesdifference unevenness spots sability No. (g/d) (70) (grade) (71)per in (times) The dyeing difference shown in the above table was a: F\/De measured in accordance with the following method. 32500 A standardsample was prepared by processing an undrawn yarn immediately afterarrival at the factory. An 30 W i s g g of false A E S l s De undrawnyarn in the same lot as the sample was proo t g li" 'h to cessed 5 daysafter arrival at the factory to form a meaf li f f l a 3 t e PIPCCSS gsuring sample. The standard sample and the measuring 6 l 7 t e texturmgSpec at sample were knitted side by side to form a sample. The 9 f m f l2 h h resulting sample was dyed by dipping in a dye bath cone PYPCeSS werem t f process formed wh1le mamtammg the draw ratio at 2.2 to 2.8.taming 2 based on the weight of the sample, of C1 10 Th recess of claim1 wherein the am i bent DISPERSE BLUE 27 at 100C. for 60 minutes withthe r e P Y S b t d t 1 100 f l by at least 2 yarn guldes prov1dedbetween the false goods'to'hcluor. ram? emg mam alnea o twister and thedraw rollers and the total sum of the lowed by washing w1th water anddrying. After drying, b m 168 is adusted to a 30 t 2700 the degree ofthe difference in dye exhaustion between 40 1 i 1 f CM 10 h th thestandard sample and the measuring sample was u z i w g i e 2 2 1 1evaluated by the naked eye on the same scale as def n s g zg 91 g g 8 3ea scribed before the Examples. l P ea er an WIS er or o wh 0nd in an atroom temperature.

at we claim 1s.

12. The process of claim 1 wherem the undrawn yarn A P for prodllcmg apolyester textured y is made to run from the inlet of the heat-treatingheater which comprises drawlng and slmultaneously falseto a point 1 mmapart from it while being preheated at Pwlsting undrawn p y Y g} drawtextuf- 60 to 150C. without contacting with the heated surlng apparatusequlpped w1th a heat-treatmg heater and face of the heater, and then theyarn is brought into a false twister between feed rollers and drawrollers, Contact i h h h d surface f the heater, 1 above wherein theundrawn polyester yarn has a birefringence being defined by thefollowing equations (A n) of 0.01 to 0.05, and the draw ratio (DR) isadjusted to a value expressed by the following equations I 5 accordingto the birefringence of the undrawn polyesand ter yarn 0.03x 0.2y l5l0.3x 2y 100 g l'l376 5 DR S l 789 log wherein x is the denier of theundrawn yarn and y is the d speed of feeding the undrawn yarn (m/min.).5 2 8 13. The process of claim 7 wherein the operation is 2 Th f l l hth d started with a false twist multiplier 50 85 of that in h F O 832';e fawn yarn normal operation without bringing the yarn into f rmgencef 1h d contact with the heat-treating heater, and then the yarn 6 Process 06 am w eremt e um yam is brought into contact with the heat-treatingheater one has been f under the temperature and the false twistmultiplier is increased to apredeter- (TC)-t1me (t hours) condmonsexpressed by the folmined value lowing equations 14 Th e process ofclalm 8 wherem yarn stringmg 1s O'0486T) I 5 -21 6424 performed byinitiating the operation at a draw textur- (where 20C 5 T S 30C.)

10(2.6040.0486T) g I 10(3.2590.0526T) (where 30C 5 T i 40C.).

ing speed expressed by the equation wherein V is the draw texturingspeed, and De is the denier of the undrawn yarn, and then the drawtexturing speed is increased to a predetermined value.

15. The process of claim 1 wherein at the time of initiating theoperation, the yarn is strung up by keeping the undrawn yarn from thesurface of the heat-treating heater so that it does not come close toit, and then draw texturing of the yarn is started while passing theyarn through a zone maintained at a temperature of 50C. to 130C. nearthe surface of the heat-treating heater, and thereafter, the yarn isbrought into contact with the surface of the heat-treating heater.

1. A process for producing a polyester textured yarn which comprisesdrawing and simultaneously false-twisting an undrawn polyester yarnusing a draw texturing apparatus equipped with a hEat-treating heaterand a false twister between feed rollers and draw rollers, wherein theundrawn polyester yarn has a birefringence ( Delta n) of 0.01 to 0.05,and the draw ratio (DR) is adjusted to a value expressed by thefollowing equations according to the birefringence of the undrawnpolyester yarn -1.8349 log Delta n - 1.1376 < or = DR < or = -2.1789 logDelta n - 1.3509 and DR < or = 2.8.
 1. A PROCESS FOR PRODUCING APOLYESTER TEXTURED YARN WHICH COMPRISES DRAWING AND SIMULTANEOUSLYFASTE-TWISTING AN UNDRAW POLYESTER YARN USING A DRAW TEXTURING APPARATUSEQUIPPED WITH A HEAT-TREATING HEATER AND A FALSE TWISTER BETWEEN FEEDROLLERS AND DRAW ROLLERS, WHEREIN THE UNDRAWN POLYESTER YARN HAS ABIREFRINGENCE ($N) OF 0.01 TO 0.05, AND THE DRAW RATIO (DR) IS ADJUSTEDTO A VALUE EXPRESSED BY THE FOLLOWING EQUATIONS ACCORDING TO THEBIREFRINGENCE OF THE UNDRAWN POLYESTER YARN 1.8349 LOG $N - 1.1376 $ DR$ -2.1789 LOG $N 1.3509
 2. The process of claim 1 wherein the undrawnyarn has a birefringence of 0.01 to 0.025.
 3. The process of claim 1wherein the undrawn yarn is one which has been aged under thetemperature (T* C)-time (t hours) conditions expressed by the followingequations 10(2.604 - 0.0486T) < or = t < or = -211.2T + 6424 (where 20*C< or = T < or = 30*C.) or 10(2.604 - 0.0486T) < or = t < or = 10(3.259 -0.0526T) (where 30*C < or = T < or = 40*C.).
 4. The process of claim 1wherein the undrawn yarn is one whose moisture content is maintainedalways at not more than 1.0 % by weight from the end of spinning to theinitiation of draw texturing.
 5. The process of claim 1 wherein theundrawn yarn is brought into contact with the surfaces of feed rollersheated at 60* -120*C. for at least 0.05 second.
 6. The process of claim1 wherein the heat-treating heater is heated to from 160* to 210*C. 7.The process of claim 1 wherein the process is carried out whilemaintaining a twist multiplier expressed by the following equation 8.The process of claim 1 wherein the process is performed whilemaintaining the draw texturing speed at 75 to 600 m/min.
 9. The processof claim 2 wherein the process is performed while maintaining the drawratio at 2.2 to 2.8.
 10. The process of claim 1 wherein the yarn is bentby at least 2 yarn guides provided between the false twister and thedraw rollers, and the total sum of the bent angles is adjusted to from30* to 270*.
 11. The process of claim 10 wherein the process iscontrolled so that the yarn runs between the heat-treating heater andthe false twister for 0.13 to 0.3 second in air at room temperature. 12.The process of claim 1 wherein the undrawn yarn is made to run from theinlet of the heat-treating heater to a point l mm apart from it whilebeing preheated at 60* to 150*C. without contacting with the heatedsurface of the heater, and then the yarn is brought into contact withthe heated surface of the heater, l above being defined by the followingequations l > or = 5 and 0.03x + 0.2y - 15l < or = 0.3x + 2y + 100wherein x is the denier of the undrawn yarn and y is the speed offeeding the undrawn yarn (m/min.).
 13. The process of claim 7 whereinthe operation is started with a false twist multiplier 50 - 85 % of thatin normal operation without bringing the yarn into contact with theheat-treating heater, and then the yarn is brought into contact with theheat-treating heater and the false twist multiplier is increased to apredetermined value.
 14. The process of claim 8 wherein yarn stringingis performed by initiating the operation at a draw texturing speedexpressed by the equation
 15. The process of claim 1 wherein at the timeof initiating the operation, the yarn is strung up by keeping theundrawn yarn from the surface of the heat-treating heater so that itdoes not come close to it, and then draw texturing of the yarn isstarted while passing the yarn through a zone maintained at atemperature of 50*C. to 130*C. near the surface of the heat-treatingheater, and thereafter, the yarn is brought into contact with thesurface of the heat-treating heater.
 16. The process of claim 1 whereinbefore an undrawn yarn package being processed becomes empty, the end ofthe undrawn yarn on the package is tied with the forward end of anundrawn yarn on an undrawn yarn package to be processed subsequently,after cold drawing each end of the undrawn yarns.